Fuse construction



Jan. 23, 1962 E. A. LINK 3,018,349

FUSE CONSTRUCTION Filed April 8, 1960 2 Sheets-Sheet 1 x Q Q Q R m N 3 Q N UGU 0 I5 *4 {1 3* INVENTOR.

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I Affurnsy Jan. 23, 1962 E. A. LINK FUSE CONSTRUCTION 2 Sheets-Sheet 2 Filed April 8, 1960 INVENTOR. EdW1J7A.L12:z]C

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Alfie/Fizzy United States Patent 3,018,349 FUSE CONSTRUCTION Edwin Link, Waukesha, Wis., assignor to RT & E Corporatlon, Wankesha, Wis., a corporation of Wisconsin Filed Apr. 8, 1960, Ser. No. 20,941 6 Claims. (Cl. 200-114) :I'hisinvention relates to a fuse construction adapted primarily for use as a high voltage circuit interrupter.

The ma ority of fuses of high voltage circuit interrupters, now in common use, provide a tubular body portion forming an arc channel within which a renewable fuse link is positioned. In some instances, the upper end of the fuse tube is closed with the result that the pressure built up in the tubular body portion caused by the rupture of the fuse link exerts sufiicient force to burst the fuse tube so as to require replacement of the ent1re fuse tube assembly rather than merely requiring the re-fusing of the device. In other instances, attempts have been made to overcome this defect by using a frangible cap that breaks under high pressure. This method is not entirely satisfactory for the reason that the frangible cap must be replaced in the field.

The primary object of the present invention resides in the provision of a new and improved fuse construction designed to overcome the above noted defects.

Another object is to provide a new and improved fuse construction including a movable contact bar that is displaceable to facilitate the mounting of the fuse link and movable under the positioning pressure of one of the terminals to establish and maintain an electrical connection between the terminal and one end of the fuse link.

Another object is to provide a new and improved fuse construction that is simple in form, relatively inexpensive to manufacture and one that will give long satisfactory usage under widely varying conditionsl Another object is to provide a new and improved fuse construction that affords a simple and effective means whereby the renewal or replacement of a ruptured fuse link may be quickly and easily effected.

Another object is to provide a fuse construction in which the path of current is established and maintained through pressure contact between a yieldable assembly positioning element and one end of the fuse link through the medium of a movable contact bar.

-A more specific object resides in the provision of a slidably mounted contact bar guided for movement along a slotted path in a member disposed at one end of the fuse tube and adapted to establish an electrical connection between a fixedly positioned end of the fuse link and the resilient current carrying arm that serves to provide a thrust component against the contact bar to maintairlz it in electrical connection with the end of the fuse More specific objects of the invention will be found in both the details of its construction and the arrangement of its cooperating elements.

Other objects and advantages will become apparent from the following description of an illustrative embodiment of the present invention.

In the drawing:

FIGURE 1 is a side elevational view of a fuse construction embodying the teachings of the present inven tion;

FIG. 2 is a front elevational view of the device shown in FIG. 1;

FIG. 3 is an enlarged top elevational view of the device;

FIG. 4 is a fragmentary vertical sectional view, taken substantially on the line 4-4, of FIG. 3;

FIG. 5 is a transverse vertical sectional view, taken substantially on the'line 55 of FIG. 4; and

FIG. 6 is a horizontal sectional view, taken substantially on the line 6--6 of FIG. 1, showing the supporting means for the fuse construction.

Referring more particularly to FIG. 1 of the accompanying drawing, it will be noted that a fuse tube assembly 10, constructed in accordance with the teachings of the present invention, is releasably retained in operating position between a fixed support 11 and a yieldable support 12 respectively secured in spaced relationship on a vertically disposed insulator 13 which in turn is positioned on a suitable support by means of a mounting bracket 14.

The fixed support 11, mounted adjacent the lower extremity of the insulator 13, comprises a U-shaped strip 15 formed of current conducting material. A pair of axially aligned slots 16 interrupting the upper marginal surfaces of the-parallel legs of the strip 15 adjacent their free ends serve as a support for the fuse tube assembly 10 to be hereinafter more specifically described. A bolt 17 passing through the insulator 13 provides the mounting means for a current carrying member 18 that includes a terminal 19 to which the load line of an electrical circuit maybe electrically connected and tightening of a nut 20 on the bolt 17 serves to establish and maintain an electrical contact between the strip 15 of the fixed support 11 and the current carrying member 18.

The yieldable support 12 comprises a U-shaped spring arm 21 formed of current carrying wire. The free ends of the U-shaped spring arm 21 are retained in electrical contact between a positioning block 22 and the current carrying member 23 through the application of anut 24 on a bolt 25 that extends through the insulator 13 adjacent its upper extremity. A terminal 26 formed on the current carrying member 23 provides the means to which the power line of an electrical circuit may be connected.

The fuse tube assembly 10 comprises an open ended tube 28 formed of insulating material providing a channel or passage within which a fuse link 29 is positioned. A current conducting sleeve member 30 is secured to the lower end of the tube 28. A pair of axially aligned 'trunnions 31 that project outwardly from the sleeve member 30 are adapted to be placed in the aligned slots 16 formed in the strip 15 of the fixed support 11 to releasably retain the lower end of the fuse tube assembly 10 in proper position. A threaded stud 32 anchored in the sleeve member 30 serves, through the application -of a nut 33, to establish an electrical connection between one end of a flexible leader 34 in which the fuse link 29 is mounted.

A sleeve member 35 is fixedly positioned on the upper extremity of the open ended tube 28 in any suitable manner such as by the application of a drift pin 36. A partition 37 disposed intermediate the ends of the sleeve 35 forms an abutment for the upper end of the tube 28 and is provided with a central bore 38 through which the flexible leader 34 of the fuse link 29 may be inserted. The upper open end of the sleeve 35 projects upwardly and rearwardly from the partition 37. The side walls of this portition of the sleeve member 35 are provided with aligned slanted slots 39 that combine to form a guide means within which a contact bar 40 is mounted for sliding movement along the slots. The contact bar 40 extends through the sleeve member 35 and has its ends disposed externally of the member. A pair of flanges 41 either or both of which may be removably applied are disposed in parallel spaced relationship on the bar 40 and serve to retain the same against any appreciable axial movement within the slots 39. An aperture 42 formed in the forward wall of the sleeve member 35 affords open access to the upper portion of the sleeve member 35.

The fuse link 29 comprises a fusible element 43 mounted 3 on one end of the flexible leader 34. The other end of the fusible element 43 is electrically connected to a member 44 adapted to receive and position an insulating tube 45 lined with gas evolving and are extinguishing material that surrounds the fusible element 43. The upper end of the member 44 is of somewhat reduced diameter and provided with external threading over which a cup-shaped conductor washer 46 is receivable. An internally threaded contact button 47 serves to releasably retain the washer 46 in position on the member 44.

Prior to the positioning of the fuse tube assembly between the fixed and yieldable supports 11 and 12, the replaceable fuse link 29 is positioned within the open ended tube 28. This is accomplished by the threading of one end of the flexible leader 34 through the aperture 42 in the sleeve member 35 and through the central bore 38 of the partition 37 and thence downwardly through the open ended tube 28. After the lower extremity of the flexible leader 34 has been projected through the lower end of the tube 28, the remainder of the fuse link may be drawn downwardly through the tube 28 until such time as the lower surface of the washer 46 contacts the upper surface of the partition 37. In order to accomplish the proper positioning of the fuse link within the open ended tube 28 it is necessary that the contact bar '40 be held adjacent the upper ends of the slots 39 to afford sufiicient room to permit the passage of the washer 46 through the aperture 42 and into its properly adjusted position within the sleeve member 35. With the lower surface of the washer 46 in contact with the upper surface of the partition 37, the lower or free end of the flexible leader 34 is tensioned and turned over the stud 32 so that the tightening of the nut 33 will serve to releasably retain the flexible leader in position and establish electrical connection between the leader and the sleeve member 30.

After the fuse link 29 has be'en'properlypositioned in the fuse tube assembly 10, the trunnions 31 on the sleeve member 30 may be positioned in the slots 16 formed in the fixed support 11 and the free end of the fuse tube assembly 10 swung upwardly to a position wherein the outer portions of the contactbar 40 are engaged by the arms of the yieldable member 12. Continuing upward and inward swinging movement of the upper end of the fuse tube assembly serves to releasably retain the assembly 10 in proper operating position. The downward pressure of the yieldable element 12 serves to establish and maintain electrical contact between the contact bar 40 and the contact button 47. I

In order to facilitate the proper positioning of the fuse tube assembly 10 between the supports 11 and 12, the

sleeve member 35 is provided with an integrally formed outwardly projecting ear 48 provided with a central opening 49 adapted to receive a hot stick so that the device may be properly installed or removed .without fear of encountering high voltage potential.

The general functioning of the device is a circuit interrupter for high voltage similar to that now in common usage. The rating of the fuse link 29 is selected in accordance with the potential of the circuit in which it is applied.

Should an excessive overload occur in the circuit,the fuse link 29 will rupture causing the interruption of the circuit. While the accompanying illustration shows the application of the device in the form of a fixedly posi- 'tioned fuse, it is to be understood that the device may be used with equal facility as a drop-out fuse.

assembly positioning means to establish and maintain electrical contact between the sliding contact bar 40 and the contact button 47 that is electrically connected to the fuse link 29. The pressure built up by the establishment of an arc in the tube 45 is of sufficient strength to raise the contact bar 40 against the pressure of the yieldable support 11 to effect the expulsion of the upper portion of the fuse link 29 from the sleeve member 35. The remainder of the fuse link 29 and the leader 34 may be quickly and easily removed from the fuse tube assembly 10 by loosening the nut 33.

From the foregoing description it will readily be understood that a simple and effective fuse construction has been provided which will permit satisfactory operation of the device as a high voltage circuit interrupter and at the same time provide a device having structural characteristics that serve to insure the normal maintenance of good electrical contacts between the cooperating elements of the device and at the same time provide a facile means by which a renewal or replacement link may be readily substituted for one that has been ruptured in service.

While the invention has been described in considerable detail in the foregoing specification, it is to be understood that various changes may be made in its embodiment without departing from or sacrificing any of the advantages hereinafter claimed.

I claim:

1. The combination with a .pair of spaced terminals of a fuse tube assembly adapted for removable positioning between the terminals to establish an electrical connection therebetween, said fuse tube assembly comprising an open ended tubular member formed of insulating material, a sleeve element fixedly positioned on one end of said tubular member, a current carryingmember fixedly positioned 011 the other end of said tubular member, a

renewable fuse link releasably retained in fixed position within said tubular member, said fuse link having one end in exposed position within said fixedly positioned sleeve element and its other end electrically connected to said current carrying member disposed on the opposite end of said tubular member, and a movable contact member overlying the exposed end of said fuse link'disposed within said fixed positioned-sleeve element whereby the positioning of said fuse tube assembly between the spaced terminals serves to establish and maintain electrical connection between said movable contact member and the exposed end of said fuse link disposed within said sleeve element.

2. The combination with a pair of spaced terminals of a fuse tube assembly adapted for removable positioning between the terminals to establish an electrical connection therebetween, said fuse tube assembly comprising an open ended tubular member formed of insulating material, a sleeve element fixedly positioned on one end of said tubular member, a current carrying member fixedly positioned on the other end of said tubular member, a renewable fuse link releasably retained within said tubular member, one end of said fuse link being'fixedly positioned within said sleeve element and the other end being electrically connected with said current carrying member, a pair of axially aligned slots in said sleeve element, said slots extending upwardly and outwardly from the axis of said tubular member, the lower end of said slots being. disposed above the opening of said tubular member adjacent its axis and the other end of said slots being offset from the axis of said tubular member, and a contact bar mounted for sliding movement along said slots whereby the positioning of said fuse tube assembly between the terminals serves to establish and maintain electrical connection between said contact bar and the fixed end of said fuse link disposed within said sleeve element.

3. A fuse tube assembly comprising an open ended tubular member formed of insulating material, a sleeve element fixedly positioned on one end of said tubular member, a current carrying member fixedly positioned on the other end of said tubular member, a renewable fuse link adapted for releasable fixed positioning within said tubular member, said fuse link having one of its ends in exposed position within said fixedly positioned sleeve element and its other end electrically connected to said current carrying member, and a contact member movably mounted on said sleeve element and overlying the exposed end of said fuse link, said contact member being movable away from its position overlying the exposed end of said fuse link to facilitate the insertion and positioning of said renewable fuse link within said tubular member, said movable contact member serving to establish and maintain electrical connection between said movable contact member and the exposed end of said fuse link positioned within said fixedly positioned sleeve element upon application of said fuse tube assembly to a pair of spaced terminals that it serves to connect.

4. A fuse tube assembly comprising an open ended tubular member formed of insulating material, a sleeve element fixedly positioned on one end of said tubular member, a current carrying member fixedly positioned on the opposite end of said tubular member, a fuse link adapted for releasable fixed positioning within said tubular member, one end of said fuse link being disposed within said sleeve element and the other end of said fuse link being releasably retained in electrical connection with said current carrying member, a pair of axially aligned slots formed in said sleeve element disposed above said tubular member, said slots each having one end overlying an open end of said tubular member, the other end of each of said slots being radially offset from the axis of said tubular member, and a contact bar mounted for sliding movement along said slots, said contact bar being movable away from the axis of said tubular member to facilitate the insertion and positioning of said renewable fuse within said tubular member and movable to establish and maintain electrical connection between said contact bar and the end of said fuse link disposed within said sleeve element upon the application of said fuse tube assembly to a pair of spaced terminals that it serves to connect.

5. A fuse construction comprising a pair of spaced terminals, one of said terminals being fixedly positioned and the other of said terminals comprising a spring element, a fuse tube assembly adapted for removable positioning between said terminals to place them in electrical connection, said fuse tube assembly comprising an open ended hollow tubular member formed of insulating material, a sleeve element fixedly positioned on one end of said tubular member, a current carrying member fixedly positioned on the other end of said tubular member, a fuse link releasably retained in fixed position within said tubular member, one end of said fuse link being in exposed position within said fixedly positioned sleeve element and its other end being electrically connected to said current carrying member, and a movable contact member mounted on said fixedly positioned sleeve element and overlying the exposed end of said fuse link, said movable contact member being movable away from its position overlying the exposed end of said fuse link to uncover the open end of said tubular member to thereby permit the insertion and positioning of said fuse link within said tubular member whereby the placement of said fuse tube assembly between said terminals serves to move said contact member under the action of said spring terminal to establish and maintain electrical contact between said spring terminal and the exposed end of said fuse link disposed in said fixedly positioned sleeve element.

6. A fuse construction comprising a pair of spaced terminals, one of said terminals being fixedly positioned and the other of said terminals comprising a spring element, a fuse tube assembly adapted for removable positioning between said terminals to place them in electrical connection, said fuse tube assembly comprising an open ended hollow tubular member formed of insulating material, a sleeve element fixedly positioned on one end of said tubular member, a current carrying member fixedly positioned on the other end of said tubular member a fuse link releasably retained in fixed position within said tubular member, one end of said fuse link being disposed within said sleeve element and its other end electrically connected to said current carrying member, a pair of axially aligned slots formed in said sleeve element above said tubular member, said slots being disposed at an acute angle with respect to the axis of said tubular member, one end of each of said slots overlying a portion of said fuse link disposed within said sleeve element and the other end of each of said slots being radially offset from the axis of said tubular member, a contact bar mounted for sliding movement along said axially aligned slots, said contact bar extending through and beyond the confines of said sleeve element, and locating means on said contact bar for retaining the same against axial movement with respect to said sleeve element, said contact bar being movable away from the axis of said tubular member to facilitate the insertion and positioning of said renewable fuse within said tubular member and movable to establish and maintain electrical connection between said contact bar and the end of said fuse link disposed within said sleeve element upon the application of said fuse tube assembly to a pair of spaced terminals that it serves to connect. 

